CS 245 - Programming Languages
Programming Design Guide
You are expected to pay attention to
your code organization. Your programming should adhere to the standards explained here.
While some of the rules are due to convention, many more are pearls of wisdom distilled
from solid software-engineering principles and all of them are essential for making your
code readable and/or easy to maintain and modify/reuse. This document explains guiding
principles. For more specific formatting rules please refer to the formatting guidelines.
- Every line of code should have a deliberate effect on your program. If you are not
sure why a line is there, it shouldn't be. If your program stops working because
you removed that line of code that you don't understand, you need to understand
it before you put it back.
- Within a single program, do not copy-and-paste code, only to change a few details. Instead, declare a function parameterize it. Do copy and paste code (changing as needed) between programs.
- Use constants to avoid so-called magic numbers - numerical
values that are scattered all over your program and are difficult to understand or
- Do not debug by trying all combinations. If you (or the debugger) pinpointed a
line that doesn't work, it is important to spend the time to understand why. The
most valuable gain of programming proficiency happens right here. A bug is not
truly fixed unless you
- understood why it happened in the first place
- understood why changing the code the way you did fixed it
Scoping and Encapsulation
- Declare variables in the smallest scope possible. That is, prefer local variables over global variables.
- Elixir and Go differ in their encapsulation approaches and are reasonably distinct from Java. Still, be inspired by Java encapsulation and attempt to achieve similar ends.
Data Structure Design
There is usually more than one way to store and represent data. Some general thoughts:
- Do not store the same thing more than once, or in more than one place.
- Choose the smallest storage so that the above is true and accomplishes your
algorithmic goals. (Ie sometimes you need to store the same information in several places in order to change the time complexity of the task. For example, explicitly storing the number of items in a linked list can change some operations from O(n) to O(1).
Each languages has slightly different recommendations and norms for comments. In general, you can look at code samples posted on the class web site. I attempt to comment posted code in a manner consistent with common usage.
In addition these sites give recommendations:
Like comments, each language has a common style. Generally, Java and Go both use camelCase for almost everything (except class names that use CamelCase and constants that use upper SNAKE_CASE). Elixir uses snake_case for most things except Module names which use CamelCase with an initial capital letter. Specifics for each language are below.